Linear electrical energy generator

ABSTRACT

In an autogenous generator (1) in which electrical energy is generated by a linkage between fixed windings (2) and permanent magnets which move integrally on the alternating motion of one or more pistons of a two-stroke internal combustion engine, the cylinders (5) coupled to the pistons (4) have a conical precombustion chamber (10) opening towards the cylinders (5), the engine runs with variable compression strokes, and the magnets (3) and windings (2) are designed such that the ratio between the quantities of mechanical energy used to generate electrical energy for two different strokes of the magnets (3) is equal to the ratio between the two compression ratios obtained in the cylinders (5) in relation to the two different strokes performed by the pistons (4) integral with the said magnets (3) multiplied by the ratio between the two overall efficiency values of the engine in relation to the said compression ratios.

BACKGROUND OF THE INVENTION

The present invention concerns the autogenous electrical energygenerator sector, and more particularly generators in which themechanical energy supplied by the alternating movement of pistons in aninternal combustion engine without a crankshaft is transformed into anelectrical current by the interaction of permanent magnets, integralwith the aforesaid pistons, with fixed windings which are immersedcyclically in the magnet's magnetic field.

This type of generator is suitable for the production of electricalcurrent which can then be used either directly, for example, forlighting or heating, as well as indirectly to supply electric motorsthat can be used for different types of locomotion on land, water, inthe air or for other applications.

In any use, the generator is required to provide good performance interms of output and adjustment with minimum environmental and noisepollution.

DESCRIPTION OF THE RELATED ART

Examples already known of this type of generator have considerablelimitations in terms of the requirements mentioned above. A significantexample is given in the generator covered by patent application GB 2 219671A. With this generator, the production of electrical energy isachieved by means of the alternating motion of magnets with respect tofixed windings, with magnets integral with the pistons of an internalcombustion engine without a crankshaft. However, in terms of arrangementof parts and the design of these parts, this prior art generator differssubstantially from that of the present invention described below. Forexample, the magnets oscillate when moving with respect to a fixed pointwhich lies essentially on the median transverse section plane of thesystem comprising the windings, and, in addition, the fixed windings canalso be used alternatively to produce electrical energy that can beutilized outside the generator or to consume electrical energy to ejectthe aforesaid magnets to enable the return travel of compression of thepiston. Additionally, the dimensions of the prior art device, in linewith the energy supplied, is much greater than that needed for agenerator as per this invention, in which electrical energy is producedboth when the magnets enter the windings and when these return in theopposite direction, and in which start-up and regulation of the systemcan be done simply by modifying the amount of fuel per cycle.

General regulation of the device in the GB patent, however, both in theinternal combustion part and the electromagnetic part, is extremelycomplicated and expensive to achieve as the pressure and amount of airadmitted, quantity of fuel, and characteristic values correlated to thecurrent circulating in the windings (impedance, resistance, direction,etc.) have to be controlled electronically, cycle by cycle.

Regulation of the quantity of air admitted, for example, which in thecase of petrol combustion has to be calibrated approximately bystoichiometric measurement for both two-stroke and four-stroke engines,should be carried out independently of the above electrical values,acting on the admission of petrol and the air admission shut-off valves.The electrical values in questions should then be adjusted in turn,cycle by cycle, in accordance with the effects of the initial adjustmentjust described. This means that a proper computer facility has to beavailable to store and interpolate a large volume of data, which makesthe equipment both costly and sensitive.

The functional layout of the internal combustion engine, apart from theabsence of a crankshaft, is essentially conventional in type, and hencethe aim is to achieve good overall efficiency by maximizing the energyper cycle to obtain the high temperatures and pressures required.

While this is understandable strictly from the point of view of energyalone, it is not so with regard to pollution in that it is virtuallyimpossible to prevent the formation of toxic compounds such as nitrousoxide and carbon monoxide as the system runs as stated on an essentiallystoichiometric mixture at high temperatures inside the cylinder.

Another similar example of a linear generator consists of a Jarrettengine. While control of the "return" of the piston under compression bymeans of electric current presents less of a problem, there are all theother aforementioned disadvantages. Additionally, in order not tofurther increase losses that are already high, fresh air for the cycleis admitted into the cylinder by acoustic resonance. This can only beachieved within a restricted cycle frequency range. Also, this type ofengine is started virtually electrically and then used with a largelyfixed, very high compression ratio of the order of 26:1, which meansthat it is only really suitable for use with naphtha as a fuel and foroperation at very high fixed speeds, with the need to disperse some ofthe heat by cooling, and problems with particulates, etc.

SUMMARY OF THE INVENTION

The inventor of the present invention came to the conclusion that inorder to simultaneously resolve the problems of product pollution,design complications, the need to use intermediate accumulatorbatteries, the poor regulation capability and low efficiency, agenerator was needed in which the electromagnetic part and the internalcombustion part would together form a functional unit, fully integratedin itself, so that movement with variable piston strokes would result inthe quantity of mechanical energy produced by the internal combustionpart corresponding exactly to the quantity of energy absorbed by theelectromagnetic part to produce electric current, for any stroke, due tothe law of thermodynamics, combustion of gases and electromagnetism.

Based on this concept, using one or more precombustion chambers inaddition to the actual cylinders, an ultra-simple unit was achieved thatcould be controlled electronically, primarily by controlling only (1)the quantity of fuel admitted in one cycle and (2) the end ofcompression position of the piston or pistons. All this was achieved, aswill be described in further detail below, at very low maximum, mediumand minimum temperatures of the employed thermodynamic cycles (abouthalf that of the usual values for an internal combustion engine) , andhence virtually zero pollution, and with very high overall efficiency ofthe internal combustion part at all operation speeds.

Based on the above, the inventor devised the present invention whichconcerns an autogenous electrical energy generator in which energygeneration is achieved by a linkage between an electromagnetic systemcomprising fixed windings linked to one or more permanent magnets whichmove integrally on the alternating motion of one or more pistons of atwo-stroke internal combustion engine, that can run with variablecompression strokes, each piston completing one expansion stroke due tocombustion and expansion in the cylinder, and one compression stroke dueto the effect of the action of a component to return mechanical energy,characterized by the characterizing portion of appended claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages mentioned earlier will become evident in the detaileddescription of the generator given below, with reference to the attacheddrawings, as follows:

FIG. 1 is a longitudinal schematic section of one example ofconstruction of a single cylinder two-stroke generator as per theinvention;

FIG. 2 is a longitudinal schematic section of another form ofconstruction with two pistons facing each other and a single communalcombustion chamber;

FIG. 3 shows a schematic plan view of a generator as per the inventionequipped with four pistons in pairs integral with two combustionchambers;

FIG. 4 contains a longitudinal section of a guide construction layout ofthe magnets and fixed windings;

FIG. 5 contains a diagram of petrol combustion rate as a function of theair/petrol weight ratio of the mixture;

FIG. 6 shows longitudinal section of an example of construction with asingle cylinder equipped with auxiliary pistons for scavenging;

FIG. 7 is a curve of the overall efficiency of the internal combustionengine of a generator as per the invention;

FIG. 8 is the curve of its specific consumption;

FIG. 9 shows a type of precombustion chamber of a truncated cone shapewith two injector nozzles.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a generator in which the magnets 3 and fixed windings 2 arepositioned such that there is a reduction in their linkage as theexpansion stroke of piston 4 progresses but an increase in linkage asthe compression stroke of the said piston 4 progresses. Otherconstructions are, however, possible in which the parts are assembledsuch that the opposite occurs, i.e. in which the linkage between themagnets 3 and the windings 2 increases as the expansion strokeprogresses and vice versa.

The generator consists of a cylinder 5 in which a piston 4 runs (FIG. 1)with two identical systems of magnets 3 arranged symmetrically withrespect to the cylinder axis integral with it by means of a fork 4'.These magnets 3 are immersed in cycles in the compression and expansionstrokes performed by the piston 4 within two systems of fixed windings2, which are likewise identical and symmetrical. This immersion variesin degree depending on the length of the said stroke.

As the compression stroke progresses, as stated, the linkage between themagnets 3 and associated windings 2 increases, and conversely reduces inline with progress of the expansion stroke.

Movement of the piston 4 is caused in one direction by expansion of thecompressed gas combined with the effect of fuel combustion, and in theother direction by the action of a system designed to return tomechanical energy. For example, one or more torsion springs or anothersystem, including electromagnetic systems of a known type which useelectrical energy to return mechanical energy to the piston may beutilized.

Fuel is admitted via an injector nozzle 14, atomized so that itsaturates, approximately stoichiometrically, at least part of the volumeof air contained in a precombustion chamber 10 that is substantiallyconical in shape with a base 10' which opens towards the cylinder 5.

The piston/magnet assembly is supported by two rolling (or sliding)friction systems 15, 16 which may be fixed to the body of the saidcylinder 5, and which enable it to perform strokes a described abovewith minimum mechanical losses.

With continued reference to FIG. 1, in which the generator is atwo-stroke engine shown in the inactive position, it is easy to describeits operation. To start the engine, all that is required is to inject apreset quantity of duly fuel into the precombustion chamber 10 and onlyfor the start cycle, into the cylinder 5, and create a spark between theelectrodes 13 positioned close to the base 10' of the cone forming theprecombustion chamber 10.

The "explosion" of the air/fuel mixture projects the piston/magnetassembly towards the said springs 7, compressing them, and these springsthen re-expand to return the same quantity of "absorbed" kinetic energy,so that the piston 4 completes a given return compression stroke.

The extent of this compression stroke depends on the kinetic energyacquired by the piston 4 following the initial "explosion", from whichthe quantities of energy that are transformed into electrical energy inthe windings 2 in the stroke paths in both directions as well as thevarious losses are deducted.

The resultant residual kinetic energy of piston 4 then converts into acompression stroke of specific length.

At the end of this compression process, the density, and hence the massof air contained inside the precombustion chamber 10, will haveincreased to an extent corresponding to the compression value obtained,and a quantity of petrol equivalent to or slightly more than thecorresponding stoichiometric quantity should then be injected by meansof injector nozzle 14. This fuel will then be ignited with theelectrodes 13. If the electromagnetic system is designed and constructedin accordance with the invention, i.e. such that, for the compressionstroke and for the associated piston speed curve, which increases withcompression, the mechanical energy absorbed by the said electromagneticsystem to produce electrical energy in the forward and return stroke ofthe piston 4 will be exactly equal to the energy generated in thecombustion cycle (net of output). As a result, the piston 4 willcomplete one expansion stroke plus one return compression strokestopping at exactly the same point as before with no change incompression ratio.

By injecting the same quantity of fuel for an indefinite number ofcycles, the operation of the generator under steady-state conditions isobtained.

To increase the electrical energy produced in a cycle, it is only amatter of increasing, by a predetermined amount, the quantity of fuelinjected into the precombustion chamber 10.

The increase in energy produced by combustion compared with the lastcycle under steady-state conditions is divided between an increase inthe quantity of electrical energy produced and an increase in thecompression ratio. This establishes a new value that is again dependentsolely on the new position adopted by piston 4 at the end ofcompression. The quantity of fuel appropriate to the greater mass of aircontained in the precombustion chamber 10 should then be injected toadapt to the new conditions, and steady-state operation will be realizedunder the new conditions. Steady-state operation for this newcompression stroke and for the relative speed curve for the piston 4,requires the energy absorbed by the electromagnetic system (i.e. thequantity of electrical energy generated in the cycle divided by theelectromagnetic efficiency) is exactly the same as the new value ofenergy supplied by combustion under the new conditions. The same appliesfor deceleration and a reduction in piston stroke, although in this casethe quantity of petrol per cycle should be reduced instead of increased.

The inventor recommends increasing saturation of air in theprecombustion chamber 10, under steady-state conditions, by about 20%compared with the exact stoichiometric value, i.e. and air/petrol weightratio 12.2.

Under these conditions, swift acceleration and deceleration of thepiston 4 can be achieved by increasing or decreasing the quantity offuel, as explained, by up to 14% compared with the preceding cycle.Maintaining the mixture conditions inside the precombustion chamber 10at all times to enable a combustion velocity that is as close aspossible to the optimum (see FIG. 5) , with the relative advantages ofcycle configuration and its thermodynamic efficiency. If rich mixturesare used in the precombustion chamber 10 when the speed is varied, theeffects on a generator as per the invention will be substantiallydiminished with regard to pollution. Combustion causes immediate, veryrapid expansion with relative containment of the temperature of themixture, which apart from anything else mixes with the very considerablevolume of air contained in the cylinder 5 which is at a relatively lowtemperature under all operating conditions. As a guide, in anexperimental prototype operative in steady-state with a maximumcompression rationρ=8.5, a maximum cycle temperature of approximately756° C. (1029° K.) and a discharge temperature of about 164° C. (437°K.) are obtained, with (λ_(v))=10.

Under these conditions, production of toxic substances from combustion(NO_(x), CO) of virtually zero can be obtained.

The combustion procedures described, which are made possible by usingprecombustion chamber 10, also enable the energy per cycle to be varied,keeping the compression stroke the same, or vice versa with no otheradjustment and no negative effects. For a load which may vary, thequantity of fuel per cycle on compression may be varied to keep thestroke the same thereby adapting the energy produced each cycle to theloads current requirement.

Engineers in the field may determine the various characteristicoperating curves, the geometric dimensions of the engine and parts ofthe generator, and the type of regulation connected with the type ofload, as well as the percentage increase or decrease in the quantity offuel per cycle to be provided in the various operating situations.Advantageously, a generator as per this invention, within its sphere ofuse, as the compression stroke increases, the effective voltage at thewinding ends increases along similar curves at a level higher than thefirst. This also applies to the quantity of energy per cycle in thesimplest case in which the load is purely ohmic. The above-mentionedsingle phase current produced by the generator can be rectified withdiodes or modulated in other ways using a converter, depending on theuser's requirements, thus enabling a direct supply to electric motors ina vehicle without the need for intermediate accumulator batteries.

To regulate operation of the internal combustion engine, the position ofthe end of the compression stroke of the piston 4 is recorded and fedinto a central electronic unit (not shown). The electronic unitregulates the quantity of fuel admitted in one cycle by the injectornozzle 14 depending precisely on the position reached by the piston 4 inthe preceding cycle, as stated, and/or on the load, increasing orreducing this as required, where necessary, by means of an increase orreduction command given, for example, by varying the angular or linearposition of an accelerator pedal or another component fulfilling asimilar function.

For an engine of a capacity of around 35 hp constructed with theparameters mentioned and with a variation in the quantity of fuel percycle equivalent to the aforesaid 14%, a transition from minimum tomaximum power output conditions is achieved in less than 2 seconds.

If the fuel admission is cut off completely, however, the pistons stop,after a very brief residual "inertia" stroke, in the position in whichthe compression resistance of gas contained in the cylinder 5 isequivalent and opposed to the resulting force of attraction between themoving magnets 3 and the other magnetized parts, or even those that areferromagnetic only, connected to the fixed winding system 2.

The latter parts are not shown on the drawings, as they may veryconsiderably in shape and arrangement depending on the designer'swishes.

To ensure correct operation of the generator, the ratio between thequantities of mechanical energy absorbed by the generator (equivalent tothe quantities of electrical energy generated divided by the respectiveelectromagnetic efficiency ratios) for operation with two differentcompression strokes in an internal combustion engine, should besubstantially the same as the ratio between the two correspondingcompression ratios multiplied by the ratio between the two overalloutputs of the engine itself in relation to these compression ratios.

As a numerical example, consider two different strokes of a piston (andhence the associated magnets), two compression ratios are obtainedequivalent to 8.5:1 and 3.6:1 and that the overall efficiency values ofthe internal combustion engineer are 0.46 and 0.30 respectively forthese compression ratios.

To achieve the preset aims, the magnets and windings have to bedimensioned also according to the type of load, the electrical values ofwhich may be controlled, such that the ratio between the quantities ofenergy consumed by the electromagnetic part of the generator in the twodifferent relative cycles, i.e. during one compression stroke and oneexpansion stroke of the piston corresponding to the said compressionratios, is equivalent to (8.5/3) (0.46/0.30)=3.6. Thus, the mechanicalenergy consumed by the magnets in one cycle of movement corresponding tothe compression ratio of 8.5 should be 3.6 times greater than thatconsumed in a cycle corresponding to the compression ratio 3.6.

This means that the two different quantities of fuel that can be mixedapproximately stoichiometrically with two different mass amounts of aircontained in the precombustion chamber in relation to the saidcompression ratios will supply exactly the right amount of energy, netof output, to move the magnets as electrical energy is generated.

If the load between the windings is purely ohmic, this can also beachieved solely by physically dimensioning and shaping the magnets andwindings, as explained below, so that this fact occurs automatically forany compression stroke. Otherwise, the quantity of fuel per cycle and/orthe electrical values relating to the load can be varied, as explainedpreviously.

The internal efficiency of the actual functional part of the generatorthen determines the quantity of electrical energy actually generated bythe various compression strokes of the internal combustion engine.

The above can be achieved physically, for example, by increasing thenumber of coils in the windings 2 either in linear mode or followingother appropriate curves in the direction of penetration of the magnets3 inside them (see arrow in FIG. 4); designing the shape of the magnets3 accordingly; and/or varying the electrical values relating to theload.

Other systems are, however, available for an expert in the field,including the use of several magnets essentially parallelepiped in formand fixed windings (FIG. 4) arranged and dimensioned such that theelectrical energy generated in one cycle in their relative movement fordifferent strokes (which is the integral ∫Vi dt in the cycle time),follows a curve that can be rectified in shape by letting it match withthe curve of energy generated in one cycle of the internal combustionengine (net of output) by varying, for example, the thickness of themagnets, their width and or the air gap (T in FIG. 4) in the directionof travel. These variations do not necessarily have to be implemented.The designer may also decide to use magnets that are parallelepiped inshape, varying the part of the volume of air mixed in the precombustionchamber and/or the quantity of fuel used to saturate it such that thequantity of energy generated by the engine at any speed is the same asthat used by the generator to produce electrical energy.

This is particularly easy if the load is taken as purely ohmic and ofconstant value (FIG. 4).

The type of combustion obtainable with one precombustion chamber 10operating as described, or preferably two precombustion chambers placeddiametrically opposite and facing 110 (see FIG. 9), is more similar tothat obtained with a burner rather than the conventional combustion withan internal combustion engine, and as stated, affords very lowtemperatures inside the cylinder, which together with the abundance ofoxygen for completion of combustion, largely guarantees freedom fromtoxic products such as CO, HC and NO_(x).

The precombustion chambers shown in FIGS. 1, 2 and 6 are conical inshape with just one injector nozzle 14 provided on the apex, but it maysometimes be useful to use precombustion chambers that are, for example,sub-cylindrical or truncated cones in shape with an injector nozzle 111set in a predetermined position perpendicular to the precombustionchamber axis (FIG. 9). If the cylinder 9 is connected by means ofappropriate ducts 112 to the closed base 113 opposite that facing thecylinder 9, it is possible to saturate to the required extent just partof the total volume of air contained in the precombustion chamber.

A second injector nozzle 114 fitted to the said closed base 113 can beused for the initial starting cycle only. With this latter arrangementand the precombustion chambers facing, it is possible to completelyeliminate any residual HC due to the very high turbulence generated bycollision of the two volumes of mixture during their expansion andcombustion. Other arrangements with one or more injectors are alsopossible.

The process described so far concerns cases in which the internalcombustion engine is supplied with fuels with low ignition temperatures,such as petrol, alcohols or gaseous fuels. Diesel or similar fuels canalso be used. For this, two injector nozzles in a single precombustionchamber (as in FIG. 9) are provided, with the first injecting petrol,for example, with appropriate time, just for the transitory enginestarting period until an adequate compression ration is reached forself-ignition of the diesel, which is then injected by the secondnozzle. This solution may be recommended in the case of high capacitystatic generators, in which the maximum output may predominate inimportance with regard to the problem of particulate emission.Particulate emission may be limited by partially recycling exhaustgases, as described below.

With this type of operation, very low temperatures can be maintainedcompared with similar convention type engines.

As mentioned, the piston/magnet assembly can be supported in motion by,for example, two or more rolling friction bushings 15 which slide alongthe guide pins 16 (FIG. 1) or similar devices, to minimize friction. Inthis case, in view of the low temperatures reached, there is no need toprovide for lubrication of any of the moving parts. No cooling system isrequired either, and it is in fact expedient to insulate the internalcombustion engine so that its operation is adiabatic.

As the internal combustion engine is a two-stroke type, for each cycle,air needs to be introduced to refill and scavenge the cylinder orcylinders. One preferred embodiment achieves this by the movement of anauxiliary scavenging piston 19 in FIG. 6 which, when moving, is integralwith the piston 4 of the engine, and which, during the compressionstroke of the piston, draws in air inside the cylinder 20 which holds itby means of a one-way valve 21. During the expansion phase of the abovepiston 4, it compresses this air up to the moment when a second one-wayvalve 22 lets it enter the precombustion chamber 10 and relativecylinder 5, due to the drop in pressure occurring in the interim in thecylinder 5 of the engine.

With this system, scavenging efficiency values of a value approaching0.90 can be achieved without any problem. More importantly, these areessentially constant for any compression stroke and hence any quantityof fuel per cycle.

The same result can be achieved with an auxiliary piston 19' in FIG. 9,which is integral with piston 6 and uses part of said cylinder 9 of theengine as an auxiliary cylinder 20', in accordance with the well-knownmethod in the field of two-stroke engines with intrinsic scavenging.This solution as shown in FIG. 9 for the case of opposite pistons, isexplained below.

As the effective expansion stroke of piston 4,6 of the engine isequivalent only to the corresponding length of the cylinder 5,9 whereasthe compression stroke of the auxiliary piston 19,19' is equal to thesum of this length plus the compression stroke of the springs. By takingaction at the design stage, a diameter can be chosen for the auxiliarypiton 19,19'; larger, the same, or smaller than that of the enginepiston depending on whether total or partial scavenging of thecombustion gases is required for a given speed range. For example, inthe prototype mentioned above, with an auxiliary piston 19 (FIG. 6) withthe same diameter of engine piston 4, total scavenging takes place untilthere is a compression stroke corresponding to a compression ratioequivalent to 3.5:1, and partial scavenging with a decreasing quantityof air admitted in lower strokes, until scavenging is obtainedequivalent to just 50% of the volume of the cylinder at the compressionratio taken as the minimum used, equivalent to 1.6:1. Partial recyclingof combustion gases at the lower compression ratios serves, as found toan increasing extent as the latter reduce, to keep the temperatures andhence the duration of combustion high enough to avoid the formation ofhydrocarbons in the exhaust gases in the transitory status of lowcompression on start-up of the generator 1.

For optimum operation, a cylinder temperature sensor and pressuremeasuring probe will be useful. The first of these being used toslightly vary the quantity of fuel admitted when the engine is cold(starter), and the second, again depending on the position of the pistonat the end of compression, to change the predominance of the fuelinjection pump in order to achieve efficient injection calibrated forall the operating statuses.

These components are not shown on the drawings as they are known andeasily implemented by an expert in the field.

To further simplify the construction of an autogenous generator as perthe invention, and to eliminate restricting reactions and/or vibrationsat the same time, it is expedient to use one or more pairs of pistons6,6' facing each other, preferably with a single communal detonationchamber 9 (FIG. 2). In this case it is possible to have just oneprecombustion chamber 10 (or two precombustion chambers 111 facing eachother as in FIG. 9) arranged centrally and with the longitudinal axis Hperpendicular to the axis K of pistons 6,6'. To ensure perfectsynchronization between several pairs of pistons when they areoperative, pistons 6,6' may be made integral by means of connectingdevices 8,8' (FIG. 3), these pistons operating in the same direction ata given moment in the cycle.

If components are then incorporated to return mechanical energy, i.e.the springs 7 in the case described, so that their position isadjustable in the direction of axis K of the movement of the pistonscoupled to them, different amounts of electrical energy can be generatedper cycle without varying the required frequency. Alternatively, thefrequency can be varied using the same cycle corresponding to optimumefficiency, varying the length of stroke of the pistons and hencevarying the time taken by these to do this. Implementation of continuousmonitoring of the velocity and synchronization of the pistons also meansthat the piston stroke can be varied micro-metrically so that it can bemaintained constant and perfectly synchronized. To achieve this lastresult, it is sufficient for just the position of the springs couple toone half of the pistons to be adjustable, i.e. those pistons which areconnected integrally by means of the connection device 8 shown in FIG.3.

Apparatus suitable for making the above adjustment can be in the form,for example, of a stepping motor or DC electric motor 17 connected by asystem of screws and female threads acting as a linear repeater for acomponent 18 integral with the relative spring 7.

The invention also provides for a further means of preventing vibrationdue to momentary lack of synchronization between two facing pistons. Byconnecting the mechanical parts of the generator which acts as a supportand locator for the springs 7 (in FIG. 2, these parts consist of thebody 11 which forms the housing for cylinders 5 and 5') to earth or to acomponent supporting the generator by a connector 12 of predeterminedlimited elasticity in the direction of movement of pistons 6,6', thereis no elastic yield in the connector 12, if the pistons are perfectlysynchronized as the forces acting in opposite directions on two springs7 connected to two facing pistons are equal with each other at alltimes. If, however, one of the two pistons moves in advance of theother, this will first exert force on the relative spring and then onthe elastic connectors 12, which will extract part of the kinetic energythat should be stored by the spring and then return the relative piston,under the effects of elastic hysteresis due to compression of thesprings.

This entails a deceleration in the piston return stroke and its gradualsynchronization with the other (delayed) facing it. This correction ofsynchronization entails losses, albeit slight, in the overall energybalance, and it is thus advisable to use an electronic procedure asmentioned above, modifying the spring return position in order to ensureperfect initial synchronization.

The overall efficiency diagrams (FIG. 7) of an internal combustionengine can be compared with the generator of the present invention andits specific consumption (FIG. 8). Overall efficiency has a value ofabout double that of a conventional engine at any speed.

All the component parts, their design and positioning and the regulationsystems can be modified and improved in line with the know-how of aspecialist in the field.

For example, instead of being supported by a fork 4', the magnets 2 inFIGS. 1 and 2 can be fixed to a cylindrical support provided on the sameaxis of the piston and integral with it, with parts arranged in asimilar way to that already described for the Jarrett engine. Thisembodiment is not shown in the drawings.

The constructions described and illustrated are therefore preferredembodiments that are neither limitative or binding.

I claim:
 1. An autogenous electrical generator comprising:a two-strokecombustion engine adapted for variable stroke operation, having: apiston in a piston cylinder, a precombustion chamber having a baseopening toward said piston cylinder, defining a volume containing airand providing a volume for combusting an air/fuel mixture to cause saidpiston to complete an expansion stroke within said cylinder; amechanical energy return means positioned to receive kinetic energy fromsaid piston during said expansion stroke and, on completion of saidexpansion stroke, enabling said piston to complete a compression strokeby imparting said received kinetic energy to said piston, wherein at theend of said compression stroke within said cylinder there remains acylinder volume of air between said piston and said precombustionchamber; fixed windings with connections for attachment to a load; and apermanent magnet mounted to move integrally with said piston and tointeract by flux linkage with said fixed windings to develop a voltageacross said connections and provide energy to said load, saidprecombustion chamber further comprising metered fuel injection means soas to ensure that, under any operating condition, at least part of saidvolume of air mixes with an at least stoichiometric quantity of fuelforming a mixture for said combustion, wherein said combustion of saidmixture produces the energy required for enabling said piston tocomplete said expansion stroke within said cylinder, and said mixtureduring combustion expands into said cylinder volume of air into which nofuel has been injected and said combustion is completed, wherein saidmagnet and said fixed windings are dimensioned such that understeady-state operations, for a given air/fuel ratio and with said partof said volume of air remaining constant, the relationship between afirst quantity of energy required to generate electrical energy for saidload at a first expansion and compression stroke and a second quantityof energy required to generate electrical energy for said load at asecond expansion and compression stroke is substantially equal to afirst compression ratio obtained within said precombustion chamber whilegenerating electrical energy at said first stroke over a secondcompression ratio obtained within said precombustion chamber whilegenerating electrical energy at said second stroke times the overallefficiency of said engine at said first compression ratio over theoverall efficiency of said engine at said second compression ratio. 2.The autogenous electrical generator of claim 1, further comprising aduct leading from said cylinder to said base of said precombustionchamber for providing said part of said volume of air.
 3. The autogenouselectrical generator of claim 1, wherein said magnet and said fixedwindings are positioned such that said flux linkage is reduced as saidexpansion stroke progresses and said flux linkage increases as saidcompression stroke progresses.
 4. The autogenous electrical generator ofclaim 1, further comprising:an ohmic load of constant value connected tosaid connections, and wherein the shape of said magnet and positioningof said magnet relative to said fixed windings establishes saidrelationship.
 5. The autogenous electrical generator of claim 4, whereinsaid magnet is essentially parallelepiped having a thickness, width, andan air gap between said magnet and said fixed winding, andwherein saidmagnet moving integrally with said piston generates electrical energy atplural different piston compression strokes that follows a curvesubstantially coincident with a curve of energy generated by said enginefor said plural different piston compression strokes.
 6. The autogenouselectrical generator of claim 1, wherein said precombustion chamber issubstantially conical in shape and further comprises a fuel injectornozzle at the apex of said precombustion chamber.
 7. The autogenouselectrical generator of claim 1, wherein said precombustion chamber issubstantially a truncated cone in shape and further comprisesa ductrunning from said cylinder to said base; a first fuel injector nozzlepositioned axially on said base; and a second fuel injector nozzlepositioned perpendicular to the axis of said precombustion chamber. 8.The autogenous electrical generator of claim 1, further comprising:anadditional piston mounted facing said piston; an additional fixedwinding; and an additional magnet mounted to move integrally with saidpiston and to interact with said additional fixed winding.
 9. Theautogenous electrical generator of claim 8, further comprising:a thirdpiston connected to said piston to cause said third piston and saidpiston to move in unison; and a forth piston connected to saidadditional piston to cause said forth piston and said additional pistonto move in unison.
 10. The autogenous electrical generator of claim 8,further comprising a combustion chamber common to said piston and saidadditional piston,wherein said precombustion chamber is mounted on anaxis perpendicular to an axis formed in said combustion chamber betweensaid piston and said additional piston.
 11. The autogenous electricalgenerator of claim 10, further comprising an additional precombustionchamber, wherein said precombustion chamber and said additionalprecombustion chamber are mounted diametrically opposite each other. 12.The autogenous electrical generator of claim 8, wherein said mechanicalenergy return means further comprises an adjustment means adjusting theamount of energy returned to said piston.
 13. The autogenous electricalgenerator of claim 8, wherein said mechanical energy return meansfurther comprises an adjustment means for relocating said mechanicalenergy return means along the axis of movement of said piston.
 14. Theautogenous electrical generator of claim 1, wherein said mechanicalenergy return means further comprises a support connectable to an anchorhaving elasticity in the direction of movement of said piston.
 15. Theautogenous electrical generator of claim 1, further comprising:anauxiliary scavenging piston having first and second single-way valves,said auxiliary scavenging piston moving integral with said piston, anddrawing in air in a compression stroke of said piston via said firstsingle-way, and expelling air via said second one-way valve to saidprecombustion chamber during an expansion stroke of said piston.
 16. Theautogenous electrical generator of claim 1, wherein under steady-stateoperation, said fuel injection means mixes said part of said volume ofair with a quantity of fuel equivalent to 120 percent of astoichiometric quantity.
 17. An autogenous electrical generator withreduced emissions comprising:a two-stroke combustion engine, having: apiston in a piston cylinder; a precombustion chamber having a conicalshape, a base opening toward said piston cylinder, defining a volumecontaining air and providing a volume for combusting a air/fuel mixtureto cause said piston to complete an expansion stroke within saidcylinder; and electrodes located within said precombustion chamber tocombust said air/fuel mixture; a mechanical energy return meanspositioned to receive kinetic energy from said piston during saidexpansion stroke and, on completion of said expansion stroke, enablingsaid piston to complete a compression stroke by imparting said receivedkinetic energy to said piston, wherein at the end of said compressionstroke within said cylinder there remains a cylinder volume of airbetween said piston and said precombustion chamber; metered fuelinjection means so as to ensure that at least part of said volume of airmixes with an at least stoichiometric quantity of fuel forming a mixturefor said combustion; combustion control means combusting said mixtureprior to any fuel entering said cylinder, whereby said combustion ofsaid mixture produces the energy required for enabling said piston tocomplete said expansion stroke within said cylinder, and said mixtureduring combustion expands into said cylinder volume of air into which nofuel has been injected and said combustion is completed with minimumtoxic NO_(x), CO combustion products.
 18. An autogenous electricalgenerator of claim 17, further comprising:fixed windings withconnections for attachment to a load; a permanent magnet mounted to moveintegrally with said piston and to interact by flux linkage with saidfixed windings to develop a voltage across said connections and provideenergy to said load; and electrical energy control means responding to achange in said load by controlling said piston stroke length.